Road machine



May 25,1937.

c. A. GUSTAFSON 2,081,536

ROAD MACHINE Filed Feb. 5, 1934 2 Sheets-Sheet 1 INVENTOR. CAEL H. GUSTHFSON ATTORNEY.

May 25, 1937. c. A. GUSTAFSON- 2,081,536

ROAD MACHINE Filed Feb. 5, 1934 2 Sheets-Sheet 2 I N V EN TOR. Cam. 0. Gus THFSON ATTORNEY.

Patented May 25, 1937 STATES ROAD MACHINE Carl A. Gustafson, Peoria, 111., assignor to Caterpillar Tractor 00., San Leandro, Calif., a corporation of California.

Application February 5, 1934, Serial No. 709,832

6 Claims.

My invention relates to road machines of the type adapted for road maintenance work, and more particularly to means for preventing the transmission of bouncing movement of the ground supports or engaging members of the machine to the earth-engaging means when the machine is travelling over an uneven or corrugated road surface.

When vehicles with resilient tires travel over a road, especially a dirt or gravel road, corrugations or waves are formed on the road-bed, which become more pronounced during further travel of vehicles over the road due to the bouncing action of the tires in passing over the corrugations. When a road maintenance machine is refinishing such a road, the front wheels thereof travel over the corrugations of washboard surface ahead of the blade;.and the bouncing action of the front wheels is transmitted through the frame to the earth-engaging means or tool, which, as a result, forms another set of corrugations.

The transmission of the bouncing action of the wheels of the road machine to the frame is particularly troublesome in present day h speed road machines equipped with resilient wheels, such as wheels having pneumatic tires. I have found that the transmission of such bouncing action to the frame of the machine can be prevented by opposing the bouncing action of the wheels. Preferably, in road machines where a solid or non-resilient connection is provided from the frame to the front axle whereby movement of the axle in a vertical direction is imparted to the frame, such opposing action is provided by means including a weight which is resiliently supported on the frame. It is desirable that the means oppose upward movement when the wheels encounter a road corrugation, and oppose downward movement when the wheels are leaving a road corrugation, so that bouncing action is counteracted, and the frame remains substantially unaffected.

It is an object of my invention, therefore, to provide a road machine of improved construction which is adapted to refinish a road surface having corrugations therein to a smooth road surface free from such corrugations.

It is a further object of my invention to provide a road machine of improved construction in which the bouncing action of the front ground supports in passing over road-bed corrugations is overcome and therefore is not transmitted to the earth-working means.

Another object of my invention is to provide in a road machine a method of preventing the bouncing action of the front ground supports, thereby preventing vibration from being transmitted to the earth-working means.

Another object of my invention is to provide an improved road machine having a solid connection between the frame thereof and the front axle which carries ground-engaging wheels and vibration damping means for absorbing the bouncing action of the wheels in travelling over roadbed corrugations.

Other objects will appear as the description progresses.

Description of figures Fig. 1 is a side elevation of an automotive road machine illustrating a preferred embodiment of the invention.

Fig. 2 is a front elevational view of the road machine illustrated in Fig. 1.

Fig. 3 illustrates a second modification of the preferred embodiment in my invention.

Desm-iption, of machine An automotive road machine disclosed herein, with which the invention is preferably employed, comprises a main frame including symmetrically disposed side members II), II (Figs. 1 and 2) which are connected by suitable cross members including front bolster l2. The frame is provided with steerable front supports or wheels l6, which are described more specifically hereinafter, and driving rear supports or wheels l1. Motor 2|, located at the rear of the machine, above rear wheels l1, provides a suitable drive for said wheels, controlled from the operators station by suitable means including gear shift lever 22.- Steering wheel 23 at the operators station controls front wheels IS.

The road machine is equipped with suitable earth-engaging or earth-working means in the form of a conventional maintenance blade which is adjustably supported underneath the frame of the machine for vertical and transverse adjustments with respect thereto, and for angular adjustment about a vertical axis to vary the angle thereof with respect to the line of draft. The adjustment of the tool is controlled from the operators station by suitable means. Blade 26 (Fig. 1) is adjustably mounted on circle 21 which is supported for rotation in a suitable circle-carrying frame, including drawbars 28, and rear cross bar 29. The circle-carrying frame has a universal draft connection with the main frame of the machine as described hereinafter to accommodate movement thereof during adjustment of the tool.

The means for accomplishing vertical adjustment of the earth-engaging tool includes similar opposite telescopic lift links 3| (Fig. 1). Only one of links 3| is illustrated. Each link 3| is universally connected at its lower end to an end of cross bar 29, and is universally supported at 32 on one of respective side members III, II. Tele scopic adjustment of each lift link 3| is accomplished by means of a suitable nut and screw mounted in housing 33 and operated through shaft 34 from gear box 35 controlled by hand lever 36. A suitable drive connection 31 is provided from motor. 2| to gear box 35. By vertical adjustment of respective lift links'3l, the tool can be adjusted vertically or it can be adjusted angularly about a longitudinal axis.

The means for adjusting the tool laterally with respect to the machine includes center shift link 4| (Fig. 1) connected to rear cross bar at its lower end and at its upper end to laterally shiftable rack 42 engaged with pinion 43. Pinion 43 is operated by suitable gearing in housing 44 and by shaft 48 from gear box 35. Center shift link 4| not only serves to adjust the tool laterally with respect to the machine, but also serves to prevent lateral movement thereof after the tool has been moved to an adjusted position. It is to be noted that center shift link 4| together with respective lift links 3| provide a rigid connection between blade 28 and the frame.

To adjust the angle of blade 26 with respect to the line of draft, circle 21 (Fig. 1) is rotated in the circle-carrying frame by suitable means including gearing in gear box 41, operated through shaft 48 from gear box 35.

Thus it is seen that the earth-engaging tool is capable of vertical, angular and lateral adjustment with respect to the frame of the machine, as well as for angular adjustment with respect to the line of draft.

To provide for the universal adjustment of the tool with respect to the frame of the machine, drawbars 28 (Figs. 1 and 3) converge at their front ends to asuitableconnection providing a pivotal mounting for eyebolt 5| which is pivotally secured to drawbars 28 in the usual mannerand is universally connected to the frame of the machine. Eyebolt 5| is pivoted on pin 52 mounted in connection 53 having its upper end pivotally I journaled in recess 54 in bolster I2, and its lower end pivotally journaled in complementary recess 58 in V-bracket 51 detachably secured to bolster I2. Bracket 51 embraces front axle 58 at the bottom, being pivotally connected thereto.

by pin 59. Thus, the main frame of the road machine has a vertical non-yielding or solid connection with the front axle, so that vertical movement of the front axle caused by bouncing action of wheels I5, which are here shown equipped with pneumatic tires, is transmitted directly to the frame.

Vibration damping means is provided for yieldingly opposing the bouncing action of th e wheels so that when the wheels'pass over corrugations in the road surface, the frame of the machine tends to float evenly while the resilient wheels absorb the bouncing action caused by the corrugations.

for receiving guide post 62 mounted in bolster I2.

Weight BI is resiliently supported on spring 63 seating at its upper end in annular recess 64 Said vibration damping means comprises a comparatively heavy weight 6| (Figs. I and '2) which has a vertical central aperture formed in the weight, and on-bolster I2 at its lower end. Post 62 (Fig. 1) extends through apertured boss 85 of bolster I2, and has enlarged end 88 resting on the top of connecting member 53. Nut 61 threaded on the upper end of post 82 acts as 'a stop to maintain weight GI and spring 83 on the post, and also serves to adjust the compression placed on spring 83.

From the preceding description, it will be apparent that a resiliently supported weight is provided on the main frame of the machine immediately over the point of connection of the frame with the front axle. The inertia of weight 8| by virtue of its elastic connection with the frame,

- for is, therefore, to opposemovement of the frame in response to bouncing action of the wheels, so that movement of the frame which would otherwise result is substantially prevented.

Thus, the vibration damping means compels the resilient front wheels to absorb substantially all vibratory movement caused by travel over corrugations, while the frame and the earth-engaging tool are stabilized and have a smooth travel, remaining substantially level.

In the modification illustrated in Fig. 3, the frame is provided adjacent the front end with tubular cross member II (Fig. 3) suitably secured between side members I8, II, and having bracket I2 welded thereon centrally thereof. Bracket I2 has a flat top surface against which an end of leaf spring 14 is clamped by means of U-bolts I8, embracing the end of leaf spring I4 at spaced points and also extensions ll of bracket 12. Weight 18 is secured on the outer end of leaf spring I4 by means of cap screws I8, passing through longitudinally disposed slots 88 in the top leaf of spring 14 and having threaded engagement with weights I8. Slots 88 provide for adjustment of weight I8 longitudinally of spring 14 to a desired position to obtain proper functioning of the vibration damping means. Weight I8 is positioned substantially over front axle 58 at the center thereof, and acts similarly to weight 6| of Fig. 2 to prevent the transmissionof the vertical vibrations to the frame.

The sizes of the weight and the springs to be used are varied according to the machine with which they are to be employed. For the usual typeof road maintenance machine now in use, 2. weight of from 200 to 400 pounds is satisfacory.

I, therefore, claim as my invention:

1. In a road machine adapted for road maintenance work, a frame having earth-working means supported therefrom for movement therewith, ground-engaging means supporting the front end of said frame and having a solid connection with said frame, a weight, and yield able means mounting said weight on said frame .adjacent said ground-engaging means.-

2. In a road machineadapted for road maintenance work, a frame having earth-working means supported therefrom for movement therewith ground-engagingmeans supporting said cally controlled movement of said weight with respect to said frame.

3. In a road machine adapted for road maintenance work, a frame having earth-working means supported therefrom for movement therewith, resilient ground-engaging means supporting an end of said frame and having a solid connection therewith, a weight, and resilient means supporting said weight above said resilient ground-engaging means.

4. In a road machine adapted for road maintenance work, a frame having earth-working means supported therefrom for movement therewith, wheels supporting the front end of said frame and located in front of said earth-working means, said wheels having resilient tires thereon, a solid connection between said wheels and said frame, a weight, and resilient means supporting said weight above said wheels.

5. A road machine adapted for road maintenance work comprising a frame having earthworking means supported thereby, ground-engaging supporting means for said frame and having a solid connection with said frame whereby any bodily movement of said supporting means in an upright direction is transmitted directly to said frame, and means for opposing tendency of the machine to bounce caused by travel of said supporting means over uneven road surface comprising a weight resiliently supported on said machine adjacent said supporting means.

6. In a road machine adapted for road maintenance work, a frame having earth-working means supported therefrom for movement therewith and a station for an operator; resilient ground-engaging means supporting said frame and having a solid connection with said frame; and means independent of said earth-working means said operator and said station for damping vibrationsof said frame caused by travel of the machine over uneven road surface, comprising a weight, andresilient means interposed between said weight and said frame.

CARL A. GUSTAFSON. 

